This invention relates in general to spring compressors and in particular to a new and useful spring compressor for large coil springs, especially for motor vehicle axle springs.
In a known spring compressor of this generic type, there is an axially movable groove-spring connection as rotation prevention between the cylindrical guide tube and a cylindrical threaded tube; or in another embodiment, the guide tube is connected without rotational capability to the threaded tube by a radial projection engaged in an axial guide slot (German Pat. No. 33 04 321). In both cases, the threaded tube can be inserted in telescope fashion into the guide tube. In the one form of embodiment, the threaded tube is provided on its outer surface with at least one axial groove open at both ends, in which is engaged a grooved bar spring or a tenon block fastened in, or on, the guide tube with axial mobility. In another form of embodiment, the radial projection is placed on the end of the threaded tube toward the spindle head. It is engaged in an axial guide slot of the guide tube open at the front, extending approximately over the entire length of the guide tube. In both forms of embodiment, the length of the guide tube can be either the same as the length of the guide spindle, or smaller. Each of the pressure plates is provided with a central bore whose diameter is slightly larger than the outside diameter of the guide tube, so that both pressure plates can be pushed over the guide tube. The threaded tube is provided with two diametrically opposite radial fingers whose radial length is larger than the radius of the central bore. Correspondingly, the recesses that are provided on the outside of the pressure plate away from the spindle head to hold the radial fingers of the threaded tube and prevent rotation are also arranged in diametrically opposite positions. Accordingly, the two radial enlargements in the pressure plate away from the spindle head, through which the radial fingers can be pushed in the axial direction, are also arranged diametrically opposite. Because of this diametrically opposite arrangement, both of the enlargements and of the recesses at the edge of the bore opening, there is a support surface in each case on the outside in the intermediate edge sections on which the radial fingers can rest without thereby being secured against rotation. This produces the risk of the rotation of the pressure plate relative to the threaded tube or to the radial fingers; this can lead to the radial fingers reaching the enlargements again by such a rotation during the compression of a spring or when handling a compressed spring, and thus being able to release the pressure plate.